#include <mutex>
// transaction_manager_quick_test.cpp
// 独立测试事务管理器的基本功能，不依赖SQLCC解析器
#include <atomic>
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>

using namespace std::chrono_literals;

namespace {

// 模拟类型定义（避免依赖header文件）
using TransactionId = uint64_t;

enum class TransactionState { ACTIVE, COMMITTED, ABORTED };

enum class IsolationLevel {
  READ_UNCOMMITTED,
  READ_COMMITTED,
  REPEATABLE_READ,
  SERIALIZABLE
};

enum class LockType { SHARED, EXCLUSIVE };

// 简化的Transaction类
struct Transaction {
  TransactionId id;
  TransactionState state;
  IsolationLevel isolation_level;
  std::chrono::system_clock::time_point start_time;
};

// 简化的TransactionManager（直接实现，不依赖头文件）
class TransactionManager {
private:
  std::vector<std::unique_ptr<Transaction>> transactions_;
  std::mutex mutex_;
  TransactionId next_id_ = 1;

public:
  TransactionManager() = default;

  ~TransactionManager() = default;

  TransactionId
  begin_transaction(IsolationLevel level = IsolationLevel::READ_COMMITTED) {
    std::lock_guard<std::mutex> lock(mutex_);
    auto txn = std::make_unique<Transaction>();
    txn->id = next_id_++;
    txn->state = TransactionState::ACTIVE;
    txn->isolation_level = level;
    txn->start_time = std::chrono::system_clock::now();

    transactions_.emplace_back(std::move(txn));
    return txn->id;
  }

  bool commit_transaction(TransactionId txn_id) {
    std::lock_guard<std::mutex> lock(mutex_);
    for (auto &txn : transactions_) {
      if (txn->id == txn_id && txn->state == TransactionState::ACTIVE) {
        txn->state = TransactionState::COMMITTED;
        return true;
      }
    }
    return false;
  }

  bool rollback_transaction(TransactionId txn_id) {
    std::lock_guard<std::mutex> lock(mutex_);
    for (auto &txn : transactions_) {
      if (txn->id == txn_id && txn->state == TransactionState::ACTIVE) {
        txn->state = TransactionState::ABORTED;
        return true;
      }
    }
    return false;
  }

  TransactionState get_transaction_state(TransactionId txn_id) {
    std::lock_guard<std::mutex> lock(mutex_);
    for (const auto &txn : transactions_) {
      if (txn->id == txn_id) {
        return txn->state;
      }
    }
    return TransactionState::ABORTED; // Default for not found
  }

  std::vector<TransactionId> get_active_transactions() {
    std::lock_guard<std::mutex> lock(mutex_);
    std::vector<TransactionId> active;
    for (const auto &txn : transactions_) {
      if (txn->state == TransactionState::ACTIVE) {
        active.push_back(txn->id);
      }
    }
    return active;
  }

  size_t get_transaction_count() {
    std::lock_guard<std::mutex> lock(mutex_);
    return transactions_.size();
  }
};

// 测试函数 - 不依赖GTest
bool test_basic_transaction_lifecycle() {
  std::cout << "Testing basic transaction lifecycle..." << std::endl;
  TransactionManager txn_mgr;
  bool all_passed = true;

  // Test begin transaction
  TransactionId txn_id = txn_mgr.begin_transaction();
  if (txn_id == 0) {
    std::cout << "❌ Failed: Transaction ID should not be 0" << std::endl;
    all_passed = false;
  }

  if (txn_mgr.get_transaction_state(txn_id) != TransactionState::ACTIVE) {
    std::cout << "❌ Failed: New transaction should be ACTIVE" << std::endl;
    all_passed = false;
  }

  // Test commit
  if (!txn_mgr.commit_transaction(txn_id)) {
    std::cout << "❌ Failed: Commit should succeed" << std::endl;
    all_passed = false;
  }

  if (txn_mgr.get_transaction_state(txn_id) != TransactionState::COMMITTED) {
    std::cout << "❌ Failed: Transaction should be COMMITTED after commit"
              << std::endl;
    all_passed = false;
  }

  // Test rollback on completed transaction
  if (txn_mgr.rollback_transaction(txn_id)) {
    std::cout << "❌ Failed: Rollback on committed transaction should fail"
              << std::endl;
    all_passed = false;
  }

  if (all_passed) {
    std::cout << "✅ Basic transaction lifecycle tests passed!" << std::endl;
  }
  return all_passed;
}

bool test_multiple_transactions() {
  std::cout << "Testing multiple transactions..." << std::endl;
  TransactionManager txn_mgr;
  bool all_passed = true;

  // Create multiple transactions
  std::vector<TransactionId> txn_ids;
  for (int i = 0; i < 5; ++i) {
    TransactionId txn_id = txn_mgr.begin_transaction();
    if (txn_id == 0) {
      std::cout << "❌ Failed: Transaction ID should not be 0" << std::endl;
      all_passed = false;
    }
    txn_ids.push_back(txn_id);
  }

  // Check active transactions
  auto active = txn_mgr.get_active_transactions();
  if (active.size() != 5) {
    std::cout << "❌ Failed: Should have 5 active transactions" << std::endl;
    all_passed = false;
  }

  // Commit some, rollback others
  txn_mgr.commit_transaction(txn_ids[0]);
  txn_mgr.commit_transaction(txn_ids[1]);
  txn_mgr.rollback_transaction(txn_ids[2]);

  active = txn_mgr.get_active_transactions();
  if (active.size() != 2) {
    std::cout << "❌ Failed: Should have 2 active transactions after operations"
              << std::endl;
    all_passed = false;
  }

  if (all_passed) {
    std::cout << "✅ Multiple transactions tests passed!" << std::endl;
  }
  return all_passed;
}

bool test_concurrent_transactions() {
  std::cout << "Testing concurrent transactions..." << std::endl;
  TransactionManager txn_mgr;
  bool all_passed = true;
  std::atomic<int> success_count{0};

  const int NUM_THREADS = 4;
  const int TXNS_PER_THREAD = 25;

  auto thread_func = [&]() {
    for (int i = 0; i < TXNS_PER_THREAD; ++i) {
      TransactionId txn_id = txn_mgr.begin_transaction();

      // Simulate some work
      std::this_thread::sleep_for(1ms);

      // Randomly commit or rollback
      if (i % 2 == 0) {
        txn_mgr.commit_transaction(txn_id);
      } else {
        txn_mgr.rollback_transaction(txn_id);
      }

      success_count++;
    }
  };

  // Launch threads
  std::vector<std::thread> threads;
  for (int i = 0; i < NUM_THREADS; ++i) {
    threads.emplace_back(thread_func);
  }

  // Wait for completion
  for (auto &thread : threads) {
    thread.join();
  }

  int expected_successes = NUM_THREADS * TXNS_PER_THREAD;
  if (success_count != expected_successes) {
    std::cout << "❌ Failed: Expected " << expected_successes
              << " successes, got " << success_count << std::endl;
    all_passed = false;
  }

  if (txn_mgr.get_transaction_count() !=
      static_cast<size_t>(expected_successes)) {
    std::cout << "❌ Failed: Total transaction count mismatch" << std::endl;
    all_passed = false;
  }

  if (all_passed) {
    std::cout << "✅ Concurrent transactions tests passed!" << std::endl;
  }
  return all_passed;
}

bool test_isolation_levels() {
  std::cout << "Testing isolation levels..." << std::endl;
  TransactionManager txn_mgr;
  bool all_passed = true;

  // Test all isolation levels
  std::vector<IsolationLevel> levels = {
      IsolationLevel::READ_UNCOMMITTED, IsolationLevel::READ_COMMITTED,
      IsolationLevel::REPEATABLE_READ, IsolationLevel::SERIALIZABLE};

  std::vector<TransactionId> txn_ids;
  for (auto level : levels) {
    TransactionId txn_id = txn_mgr.begin_transaction(level);
    if (txn_id == 0) {
      std::cout << "❌ Failed: Transaction creation with isolation level failed"
                << std::endl;
      all_passed = false;
    }
    txn_ids.push_back(txn_id);
  }

  // All should be active
  auto active = txn_mgr.get_active_transactions();
  if (active.size() != levels.size()) {
    std::cout << "❌ Failed: All transactions should be active" << std::endl;
    all_passed = false;
  }

  // Commit all
  for (auto txn_id : txn_ids) {
    if (!txn_mgr.commit_transaction(txn_id)) {
      std::cout << "❌ Failed: Commit should succeed" << std::endl;
      all_passed = false;
    }
  }

  if (all_passed) {
    std::cout << "✅ Isolation levels tests passed!" << std::endl;
  }
  return all_passed;
}

} // anonymous namespace

int main() {
  std::cout << "🧪 SQLCC Transaction Manager Quick Test Suite" << std::endl;
  std::cout << "==================================================" << std::endl
            << std::endl;
  std::cout << "🧪 SQLCC Transaction Manager Quick Test Suite" << std::endl;
  std::cout << "==================================================" << std::endl
            << std::endl;

  int tests_passed = 0;
  int total_tests = 4;

  if (test_basic_transaction_lifecycle())
    tests_passed++;
  if (test_multiple_transactions())
    tests_passed++;
  if (test_concurrent_transactions())
    tests_passed++;
  if (test_isolation_levels())
    tests_passed++;

  std::cout << std::endl;
  std::cout << "========================================================="
            << std::endl;
  std::cout << "Test Results: " << tests_passed << "/" << total_tests
            << " tests passed" << std::endl;

  if (tests_passed == total_tests) {
    std::cout << "🎉 All tests passed! Transaction Manager is working correctly."
              << std::endl;
    return 0;
  } else {
    std::cout << "❌ Some tests failed. Please check the implementation."
              << std::endl;
    return 1;
  }
}
